This tutorial shows how to adjust the permalinks format for custom post type added with Enfold theme. Similarly, it can be also applied to other 3rd party themes and their custom post types and taxonomies.
To remove /portfolio-item/ base or replace it with another slug, please go to Permastructure section in Permalink Manager admin panel:
Now, you can either remove the base or change the Portfolio Item permalinks to completely customized format:
How to apply the new format to old portfolio permalinks?
The new format will be automatically applied to all new permalinks. If you would like to adjust the old portfolio item permalinks, you will need to use “Regenerate/reset” tool: